Comparison of the risks and drivers of compound hot-dry and hot-wet extremes in a warming world

Compound hot-dry (CHD) and compound hot-wet (CHW) extremes have both intensified under global warming, posing exacerbated socio-economic threats compared to univariate extremes. This study presents a comprehensive assessment and comparison of the historical changes and driving factors behind CHD and CHW using observational data and climate model simulations. Findings indicate a notable surge in CHD and CHW occurrences, with CHW experiencing a higher increasing rate. Our investigation further reveals that anthropogenic climate change predominantly drives the increase in both types of compound extremes, especially for CHW. In contrast, land-atmosphere feedbacks have a limited impact on CHW at a global scale, but substantially contributes to the rise in CHD by reinforcing the negative precipitation-temperature coupling. This influence even surpasses that of anthropogenic climate change in specific regions. Understanding these variations and underlying causes is crucial for improving prediction accuracy and mitigating the impacts of compound extremes.